#include <learnopengl/shader_s.h>
#include <GLFW/glfw3.h>
#include <stb_image.h>

void framebuffer_size_callback(GLFWwindow *window, int width, int height) {
    glViewport(0, 0, width, height);
}

int main(){
// int WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nShowCmd) {
    glfwInit();

    glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
    glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
    glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);

    GLFWwindow *window = glfwCreateWindow(800, 600, "texture combined", NULL, NULL);

    glfwMakeContextCurrent(window);
    glfwSetFramebufferSizeCallback(window, framebuffer_size_callback);

    if (!gladLoadGLLoader((GLADloadproc)glfwGetProcAddress)) {
        return -1;
    }

    Shader ourShader("shader.vs", "shader.fs");

    float vertices[] = {
        0.5f, 0.5f, 0.0f,                   1.0f, 0.0f, 0.0f,                       1.0f, 1.0f,
        0.5f, -0.5f, 0.0f,                  0.0f, 1.0f, 0.0f,                       1.0f, 0.0f,
        -0.5f, -0.5f, 0.0f,                 0.0f, 0.0f, 1.0f,                       0.0f, 0.0f,
        -0.5f,  0.5f, 0.0f,                 1.0f, 1.0f, 0.0f,                       0.0f, 1.0f
    };

    unsigned int indices[] = {
        0, 1, 3,
        1, 2, 3
    };

    unsigned int VBO, VAO, EBO;
    glGenBuffers(1, &VBO);
    glGenVertexArrays(1, &VAO);
    glGenBuffers(1, &EBO);

    glBindVertexArray(VAO);

    glBindBuffer(GL_ARRAY_BUFFER, VBO);
    glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);

    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, EBO);
    glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(indices), indices, GL_STATIC_DRAW);

    // position attribute
    glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 8 * sizeof(float), (void*)0);
    glEnableVertexAttribArray(0);

    glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 8 * sizeof(float), (void*)(3 * sizeof(float)));
    glEnableVertexAttribArray(1);

    glVertexAttribPointer(2, 2, GL_FLOAT, GL_FALSE, 8 * sizeof(float), (void*)(6 * sizeof(float)));
    glEnableVertexAttribArray(2);

    // load and create a texture
    unsigned int texture1, texture2;
    
    // texture 1
    glGenTextures(1, &texture1);
    glBindTexture(GL_TEXTURE_2D, texture1);

    // set the texture wrapping parameters
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);

    // set texture filtering parameters
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);

    // load image, create texture and generate mipmaps
    int width, height, nrChannels;

    // tell stb_image.h to flip loaded texture's on the y-axis.
    stbi_set_flip_vertically_on_load(true);

    unsigned char *data = stbi_load("container.jpg", &width, &height, &nrChannels, 0);
    if (data) {
        glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, width, height, 0, GL_RGB, GL_UNSIGNED_BYTE, data);
        glGenerateMipmap(GL_TEXTURE_2D);
    }

    stbi_image_free(data);

    // texture 2
    glGenTextures(1, &texture2);
    glBindTexture(GL_TEXTURE_2D, texture2);

    // set the texture wrapping parameters
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);

    // set texture filtering parameters
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);

    // load image, create texture and generate mipmaps
    data = stbi_load("awesomeface.png", &width, &height, &nrChannels, 0);
    if (data) {
        glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, data);
        glGenerateMipmap(GL_TEXTURE_2D);
    }

    stbi_image_free(data);

    ourShader.use();

    // glUniform1i(glGetUniformLocation(ourShader.GetProgramId(), "texture1"), 0);
    ourShader.SetInt("texture1", 0);
    ourShader.SetInt("texture2", 1);

    // render loop
    while (!glfwWindowShouldClose(window)) {

        // render
        // ---------
        glClearColor(0.2f, 0.3f, 0.3f, 1.0f);
        glClear(GL_COLOR_BUFFER_BIT);

        // bind textures on corresponding texture units
        glActiveTexture(GL_TEXTURE0);
        glBindTexture(GL_TEXTURE_2D, texture1);
        glActiveTexture(GL_TEXTURE1);
        glBindTexture(GL_TEXTURE_2D, texture2);

        // render container
        ourShader.use();

        glBindVertexArray(VAO);
        glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, 0);

        glfwSwapBuffers(window);
        glfwPollEvents();
    }

    glDeleteVertexArrays(1, &VAO);
    glDeleteBuffers(1,  &VBO);
    glDeleteBuffers(1, &EBO);

    glfwTerminate();
    return 0;
}